Sheet handling mechanism for bed and cylinder printing machines



Nov. '27, 1951 F. SPENCE SHEET HANDLING MECHANISM FOR BED AND CYLINDER PRINTING MACHINES l0 Sheets-Sheet 1 Filed NOV. 50, 1946 mzj d' l0 Sheets-Sheet 2 F- SPENCE SHEET HANDLING MECHANISM FOR BED AND CYLINDER PRINTING MACHINES Nov. 27, 1951 Filed Nov. 30, 1946 Nov. 27, 1951 F. SPENCE 2,576,421

SHEET HANDLING MECHANISM FOR BED AND CYLINDER PRINTING MACHINES 10 Sheets-Sheet 3 Filed Nov. 50, 1946 Nov. 27, 1951 F. SPENCE 2,576,421

I SHEET HANDLING MECHANISM FOR BED AND CYLINDER PRINTING MACHINES l0 Sheets-Sheet 4 Filed Nov. :50; 1946 Nov. 27, 1951 F. SPENCE SHEET HANDLING MECHANISM FOR BED AND CYLINDER PRINTING MACHINES l0 Sheets-Sheet 5 Filed Nov. 50, 1946 Nov. 27, 1951 2,576,421

F. SPENCE a SHEET HANDLING MECHANISM FOR BED AND CYLINDER PRINTING MACHINES I Filed Nov. 30, 1946 1O Sheets-Sheet 6 Nov. 27, 1951 F. SPENCE SHEET HANDLING MECHANISM FOR BED Filed Nov. 50, 1946 10 Sheets-Sheet '7 Nov. 27, 195] SPENCE 2,576,421

I SHEET HANDLING MECHANISM FOR BED AND CYLINDER PRINTING MACHINES Filed Nov. 30, 1946 10 Sheets-Sheet 8 Nov. 27, 1951 F. SPENCE 2,576,421

- SHEET HANDLING MECHANISM FOR BED AND CYLINDER PRINTING MACHINES l0 Sheets-Sheet 9 Filed NOV. 30, 1946 NW. 27, 1951 F. SPENCE 2,576,421

, SHEET HANDLING MECHANISM FOR BED AND CYLINDER PRINTING MACHINES Filed Nov. so, 1946 10 Sheets-Sheet 1o p I P n v n y n NN Q Patented Nov. 27 1951 SHEET HANDLING MECHANISM FOR BED AND CYLINDER PRINTING MACHINES Fred Spence, Sale, England, assignor to Linotype 1 and Machinery Limited, London, England, a

' British company Application November 30, 1946, Serial No. 713,212 In Great Britain November 19, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires November 19, 1965 Claims; (Cl. 101-279) This invention relates to printing machines wherein sheets are fed to an impression cylinder which co-operates with a printing surface and wherein the impression cylinder is movable into and out of position to contact with the printing surface. The invention is particularly, but not exclusively, applicable to printing machines having sheet detector mechanism for ensuring that only a correctly fed sheet is Printed.

The present invention consists in a printing machine providing with mechanisms for feeding, registering and delivering a sheet and having an impression cylinder which is movable into and out of position to contact with a printing surface wherein the feeding, registering and delivery mechanisms are mounted on a support which is moved in accordance-With movement of the impression cylinder, said mechanisms continuing in operation irrespective of the position of the impression cylinder and support. Means for operating the feeding and registering mechanisms may be carried by the impression cylinder and may comprise cams which operate said mechanisms through intermediate connections carried by the support. v

Preferably the support comprises frames slidable in guideways in side members of the machine frame in which the impression cylinder is 'mounted. The shaft of the impression cylinder may be mounted in eccentric bearings which are rocked to move the impression cylinder into and out of contact with the printing surface, and the slidable frames may be connected to the bearings so as to move in accordance with movement of the impression cylinder. Each slidable frame may be connected to a bearing by means of a link which is arranged with its lowerend embracing a boss on the bearing concentric with the shaft. I

'1 The sheet feeding mechanism may include a feed-board which is'reciprocated along an ex'ten sion'mounted on the support so as to carry a sheet to the impression cylinder, Ihe sheet registering mechanism may include movable front guides againstwhich the front edge of the sheet-is brought; 'a side registering *device' which is brought down to the edge of the sheetto register a sheet at the side, and movable drop guides which hold the sheet stationary during the lift ing of the front guides and the closing of the impression cylinder grippers on to the sheet; The delivery mechanism may include a deliverychain on sprockets mounted on'a shaft which is carried by bearings in the support. 1 f j V The eccentricbearings in which the shaft of the impression cylinder is mounted may be connected to eccentrics on a shaft which is inter mittently given a half rotation by means of a continuously oscillating lever carrying a pawl. adapt ed to be engaged with a notched disc in driving connection with the shaft carryingthe eccentrics. Engagement of the pawl with thenot ched dis-c may normally be prevented by a trip cam covering a notch in the disc, said trip cam being movable to a position in which the notch is uncovered and the pawl is allowed to engage therewith. Movement of the trip cam may be con trolled by manually-operated mechanism or by sheet detector mechanism on the impression cylinder.

The invention will now be described in greater detail with reference to the accompanying draw-- ings, which illustrate one form which itmay assume.

In the said drawings:

Figure 1A is a side elevation of a printing machine embodying the present invention;

Figure 1B is a side elevation of the mechanism for moving the impression cylinder;

Figure 2 is an enlarged side view showing the support on which the sheet feeding, sheet registering and sheet deliveryv mechanisms are mounted;

Figure 3 is a sectional view taken on the line IIL- III of Figure 2;

Figure 4 is a side elevation of the means for registering a sheet at the front;

Figure 5 is a front elevation of the means for registering a sheet at the front;

Figure 6 is a side elevation of the drop guides;

Figure '7 is a plan of the drop guides;

Figure 8 is an enlargedvplan of the side registering mechanism;

Figure 8a is a view taken on the line VIIIa-VIIIa of Figure 8;

Figure 9 is a view taken on the line IX-IX of Figure 8;

Figure 10 is a view taken on the line X-X of Figure 8;

Figure 11 is a side elevation of the intermediate connections carried by the support;

Figure 12 is a plan of Figure 11;

Figure 13 is a side elevation of the impression cylinder gearand the cams thereon;

Figure 14 is a section taken on the line XIV- XI V of Figure 13; v

' Figure 15 is a side view of the mechanism for intermittently rotating the impression cylinder eccentric bearings;

Figure 16 is aside view of the sheet detector mechanism in the impression cylinder, and Figure 17 is a side view of the vacuum box and mechanism forming part of the sheet detector mechanism.

Referring first to Figure 1A, the printing surface comprises a type forme I carried by a print-- ing bed 2 which is reciprocated along tracks 3 in a machine frame 4. The upper part of the machine frame 4 has side members 5 carrying bearings 6 for the shaft 1 of a continuously rotating impression cylinder 8, to which cylinder sheets are fed for printing. The bearings 6 are eccentric bearings which may be partially ro tated to move the impression cylinder 8 away from the type forme I and may be partially rotated in reverse direction to restore the impression cylinder 8 to its original position;

The upper part of each side member 51s pro.- vided with vertical guideways 9 (see Figures 2 and 3) in which a frame I0, hereinafter referred to as a feed frame I0, is slidably arranged. A link II connected to, each feed frame I!) is arranged with the lower end lZ'thereof embracing a 11055 I3 on the impression cylinder bearing 6 concen ric with the shaft 1' and cylinder 8 so that the rota ion of the be rin s 6 nd the rise and fall of the impression cylinder 8 causes the feed fram s t to move up and down in a v rti al pla e- A bracke 4 (see Figure lA) secured to each feed frame ID is DrQvided with grooved rollers I5 forming a track along which a f e rd it havin runners I I is reciprocated to car y a she t to the impression cylinder grippers I8. The feedboard [6 is recipro ated by a lev r I9, on e d of which is fork-ed an eng g s a stud l9a o t fee'd bo rd an th t e en o w c p vided with a cam roller co-operating with a cam 26 on the impression cylinder 8. Sheets may be fed to the feed-board I6 by any suitable mechanism; such as a swinging suction gripper 2 I Means for operating the impression cylinder grippers I8' may be: provided on the side members 5 and feed frames I6. Each feed frame I6 is provided with bearings 22a, 23a and 24a (see Figure 2) for carrying respectively a front guide shaft 22 (see Figure 1A), a side register shaft 23 and a shaft 24 for carrying the sprocket 25 of a delivery chain 26; A- support 21a is also provided on each feed frame ID for a shaft 21 carrying under-guides 28 with which the arms or guides 29 on the front g-uideshaft 22 .co-operate. Studs 36 are provided on the feed frames It for the pivotal attachment of drop guides in the form of a transverse bar 3|.

The front guide shaft 22 supports means for registering a sheet at the front comprising arms 29a (see Figures 4 and 5) carrying front lays 29. The arms 29a are secured to the shaft 232, to which shaft is attached an arm 32 yieldingly trolled pusher rod 42 having a lifting member 43 contacting with an adjusting screw 44 on an arm 45 of the transverse bar 3| The adjusting screw 44 effects a quick rise of the transverse bar 3| and permits some adjustment of the timing of the action thereof.

The side register device 23 (see Figures 8, 3a, {land IO comprisesa sleeve is on which the registering member H is adjustably mounted, said sleeve 46 being slidably and rotatably mounted in one feed frame I6, a second sleeve 48 rotatably mounted the other feed frame If! but being prevented from endwise movement by a bush 49 anda rod: EIlpassing through both sleeves 46 and connected to a cam lever 33 loosely mounted on the shaft 22 and having a cam roller 34 co oper ating with cam surfaces (see Figure 2; and 13) formed on the gear 36 attached to the impression cylinder 8, The under u d 23. on to w i the lays 29 arebrought down comprise blades attached to arms 31 clamped to the square shaft 21 mounted in the feed frames ID.

The transverse bar 3t (see Figures 6 and '1) rminsthe-dr h guides is actuat by a 38 secured to the boss 39 of the impression cylinder g and intermediate connections (see Figures 11 and, 12) mounted on a feedframe H1 comprise ing a lever 4| having a roller 4m cooperating with said cam 33 and actuati a spring co 48. The side-register member 4'! is formed with a keypiece all which enters and slides in a slot 52 formed in the feed-board edge when the sidere ister member 47! is rocked in a downward direction. The side-register member 41 is adjustably carried by an arm 53 loosely mounted on the sleeve 45, the arm 53 beingconneoted by means of a spring plunger 54 to a lever. 63a adjustably clamped to the sleeve 46. Withdrawal of. the spring plunger 54 allows the arm 53 carrying the registering member ll to be turned to an inoperative position.

The rod 56 has at one end a sleeve 55 with knurled knob 56, the sleeve 55 screwing into a block 5'! provided with a recessed washer 58 bearing against a flanged collar 59 secured to the sieeve 4'6 so that endwise movement of the rod 56 is imparted to the sleeve 46, but the sleeve can be rotated relatively to. the block 51 and rod 50. A projecting pin 6b on the block 5'! engages a, socket in a feed frame It to prevent rotation of the block 51- relatively to the feed frame I0 while permitting an endwise movement of the block 51 with the sleeve 46,, A spring 6| extending between a collar 6.2; afilxed to thesleeve 46 and one side of the feed frame I6 and a spring 63 xtending between the other side of the feed frame III and the washer 58 on the block 5! ensure smoothness in the endwise movement of the sleeve 46 in either direction. Rotation of the knurled knob 66 in either direction effects adjustment of the side register member 41 within limits imnosed by a stop 64.

The sleeve 46-has secured thereon an arm 65 having an aperture 66 which is slidably engaged by a pin 6? on an arm 68 secured to the second sleeve 58 so that both sleeves. 46 andfi may be rotated together while permittin a sliding movement of the sleeve 46 relatively to the second sleeve. 43.

An endwise or sliding movement is. imparted to the rod 50 and sleeve 46 by a cam 69 secured to the impression cylinder gear 36 and intermediate connections"!!! (see, Figures 11 to 14.) carried by a bracket Illa secured to'the side of a feed frame III, For this. purpose, the rod 50 is'formed at its end opposite to that connected to the sleeve 46 with a gib 'II- which engages inan aperture I la formed in a lever 1-2 secured. to a vertical shaft I3 mounted in the bracket Illa, at the lower end of T which shall;- 3 is secured a toothed segment meshing with a segment lever 15 pivoted by a stud I6 on the bracket 10a. An arm of the se ment lever 15 is provided with a roller Il engaging the cam 69.

The cam 69 is detachably secured to the pression cylinder gear 36 so that it may be removed, reversed and replaced with the outside vertical edge as viewed in Figure 173 placed against the gear 36 so that the endwise or sidelaying stroke of the rod 50 can be made to either A rotary or oscillating movement is imparted to the second sleeve 48 by a cam I8 secured to the boss of the impression cylinder gear 36 and inter-- mediate connections I9 carried by the bracket 10a. For this purpose the second sleeve 48 has secured thereto an arm 88 pivotally connected at one end to a link 8| which at its other end is pivotally connected to a lever 82 on a horizontal spindle 83 mounted in bearings in the bracket 10a, the other end of the spindle 83 having secured thereto a cam lever 84 having a roller 85 engag.- ing the cam 18.

The means for oscillating the impression cylinder bearings 8, and hence for moving the impression cylinder 8 into and out of contact with the printing surface I, comprise adjustable links 86 (see Figures 1A and 1B) connected between arms 81 on the impression cylinder bearings 8 and eccentrics 88 secured to a shaft 89 (see Figure 15) mounted in the machine frame. The shaft 89 has also secured thereto a toothed pinion 90 in permanent mesh with a gear wheel 9| rotating freely on a stud 92 secured in the machine frame, the gear wheel 9| having twice as many teeth as the pinion '90. A disc 93 with four evenly spaced notches 94 in its periphery is keyed to the boss 95 of the gear wheel 9| and between the gear wheel 9| and the disc 93, a trip cam 96 isv loosely mounted on the boss 95, the trip cam 96 being drawn towards a stop 91 by means of a tension spring 98.

- Freely mounted upon the stud 92 is a lever 99 carrying a stud I upon which is pivoted a pawl |0| adapted to engage under the influence of spring .I0|a with the notches 94 in the disc 93. The lever 99 is connected by a link I82 to a cam lever I93 (see Figure 1B) which is rocked to and fro by a cam I04 on the main cam shaft, once for I each revolution of the impression cylinder 8. The parts are so arranged that the pawl-carrying lever 99 moves through ninety degrees for each stroke ofthe cam lever III-3 so that, when the pawl I0| is allowed to engage in one of the notches 94 the disc 93 and the gear wheel 9| are turned through a quarter revolution and consequently the shaft 89 on which the pinion 99 and eccentrics 88 are mounted is caused to perform half a revolution to turn the eccentric bearings 6 and move theimpression cylinder 8 towards or away from the printing surface I. The shaft 89 may be provided with a locking plate I05 (see Figure having notches I06 which are engaged by a roller I0I on an'arm I08 influenced by an adjustable spring I09 so that the shaft 89 is held in the position to which it is turned.

The trip cam 96 is normally held away from its stop 9"! by a lock arm 0 andcovers a notch 94 to prevent engagement of the pawl IOI therewith (as shown in Figure 13). So long as this condition of the parts is maintained, the pawl IOI rides idly on the periphery of the disc 93 during the to-and-fro movement of the lever 99 and no rotation of the disc 93 and gear wheel 9| oc-.- curs.

The lock arm |I0 which is pivoted on a stud III secured to the machine frame may be given a slight rotation in a clockwise direction by means of a cam II2 which is pivoted to the machine frame and acts on a roller I I3 carried by the lock arm IIO. Such rotation of the lock arm IIO releasesthe-trip cam 96 and allows it tobe moved by the spring 98 into contact with its stop 91, as shown: in Figure 15.

Movement of the trip cam 99 uncovers a notch 94, so allowing the pawl IOI, when the lever 99 is at the commencement of its stroke, to enter the notch 94. The ensuing movement of lever 99 through ninetyv degrees rotates the disc 93 through a quarter revolution to cause the shaft 89 to make half a revolution and the impression cylinder 8 to move away from the printing surface I.

Near the end of its stroke the lever 99 carrying the pawl |0I engages an abutment II4 on the trip cam 96 and so returns the trip cam to the position in which thelock arm I I0 again looks it., On the subsequent return movement of the lever 99, the pawl .IOI is lifted out of engagement with the notch 94 by the trip cam 98 and remains in disengaged position. When the lock arm III] is again actuated by the cam N2 the trip cam 96 is again released and the pawl I0| is allowed to engage the next notch 94 to turn the disc 93 and gear wheel 9| through a quarter revolution. The.

shaft 89 carrying the eccentrics 88 is then turned through half a revolution and the impression cylinder 8 is returned to printing position. The

. shaft 89 is turned always in one direction, half a revolution effecting the tripping of the impression cylinder 8 and the succeeding half revolution effecting the return to printing position.

The cam H2 is connected by a lever H5 and link III; to a hand lever H! (see Figure 16) secured to a shaft |I8 journalled in the machine frame. As there are four notches 94 in the disc 93 which could (if allowed by the trip cam) make a quarter rotation for each operative stroke of the lever 99 and each revolution of the impression cylinder 8, it would be possible, by manipulating the hand lever I I I, say twice within a single revolution of the impression cylinder 8, to alter the phase'relation between the shaft 89 and the impression cylinder 8, so that the latter would then be in a position for contacting with the printing surface Iqat a time when it should be out of such position and vice versa. To prevent the occurrence of this condition, the gear wheel 9| is provided with cam pieces I I9 which are arranged to engage a nose-piece I20 on an arm I2| carried by the stud I I I. An abutment I22 on the arm |2I engages a similar abutment (not shown) on the cam II2. If the shaft 89 is out of phase with the impression cylinder 8, one or other of the cam pieces II9, through the arm |2|, moves the cam II2 into the position it should occupy when the impression cylinder 8 is out of position for contacting with the printing surface I.

The impression cylinder 8 may be tripped by operation of the hand lever I H or by the operation of the sheet detector mechanism now to be described, with reference to Figures 16 and 1'7.

The gripper bar I23 of sheet-receiving grippers I24 on the impression cylinder 8 is pierced with small holes I25 which are in alignment with similar holes I26 in the grippers I24 when the latter are closed on to the bar. The holes I25 are connected by pipes I21 with a vacuum box I28 which is hermetically sealed by a flexible diaphragm I29 and which is located in the impression cylinder 8. A passage I30 in the impression cylinder wall intermittently; connects with a fixed port |3I and causes the vacuum box I28 to be-put into intermittent communication with an external vacuum chamber I32 which may be exhausted by means of ,a vacuum pump.- 7

The flexible diaphragm I29 is connected to pivoted stop finger I33 engaging a notch I34 in a collar I35 secured toa shaft I36 journalled in acvcgsai.

7. the impression cylinder 8. The relationbetween the diaphragm I29 and the stop finger I33 is such that when the pressure in the vacuum box 128 is less than atmospheric pressure (with consequent.

deflection of. the diaphragm'i the stop: finger I33 acts in opposition to a spring I31 to'hold the shaft- I3B: against rotation. The shaft I36 projects through an end wall of the cylinder 8,. and has secured thereto'a cam lever I38 carrying a roller I39 which engages a cam I40 freely mounted. on the boss of the. impression cylinder and constrained to move in a vertical plane without ro-' tation by a fixed stud HI whichengagcs a er-ti cal. slot 142111 the lower. end of the cam I 40. The roller I39 is'positioned so that normally'it passes through a cam slot 143 in a lever I attached tothe han'dalever I IT.

A. sheet properly held between the grippers I24 and. gripper bar I23 closes: the holes I25 and- I25 and prevents access of air to the vaccum Ibex I28 which has been put. in communication. with the vacuum chamber 132'. The pressure in the vacuum box 123 is then. below atmospheric pres.-

sure and the flexible diaphragm I523 is-deflected.

downwardly, soholdingv the stop finger I 33 in contact with the notched collar. 35 and thereby preventing rotation of theshaft 133; The roller I39 on lever I38 thenpass'esfreely through the camslot I43.

If there is not sheet between the grippers and gripper bar or if the sheet is incorrectly posh:

tioned, one at least of the holes. I25: is not covered. and air is admitted to the vacuum box I28, so

equalizing the pressure on both sides of the diaphragm I29, thus decreasing the deflection thereof and tending to release the stop finger 133 from the notched collar I35. The notch 134 is undercut so that release of the stop finger I 33 is deferred until the shaft I36 is given a. slight turn bythe roller I39 engaging thehigh part of the cam I453.

The stop finger I33 is then disengaged. from'the collar I35 and the shaft I36 is free to turn under the influence of. the spring I31 toan: extent determined by the shape of the cam I411. The pa sition" of the roller I39 is-now such that itengages with the sideof. the slot M3 (as shown-in dotted lines in Figure 16) andmoves the-lever I44 and handleverIlI to trip the impression-cylinder :8. The printing machine continues to with the impression cylinder 8 out of position forcon-F tacting with the printing surface I until acorrectly fed sheet closes the holes I25 and I23 and restores the impression cylinder 8 to its printing position. When there is. no sheet in the: grippers I24 the. impression cylinder 8 may bezmoved into position for contacting with the printingysurface I= by operation of the hand lever I'I'I but the. int-:- pression cylinder will be automatically trippedv on the succeeding revolution of the cylinder unless a sheet has been correctly fed in the meantime.

With a sheet which had beencorrectly red. but which was defective in length, the impression cylinder 8 would normally remain in position for contacting with the printing surface I so that part of the impression would be 'taken on the impression cylinder packing unless the handlever II"! were depressed beforethe positionfireazched by the impression cylinder at which tripping could occur (as determined by cam The time lapse which occurs between the 'feed ing of the sheet to the grippers and the latest point for tripping the impression cylinder gives the open ator an opportunity to depress the hand lever II! in time to prevent sets-off of the impression l the arms 29a rise.

on to theimpression cylinder packing. The impression cylinder is then tripped for one revolu-- tionand returns automatically to the position for contacting with the printing surface if thesucceeding sheet has been correctly fed.

The sheet feeding and registering mechanism is continuously in operation, a; sheet deposited on the feedboard I8 being brought thereby to-a. position in which the front edge-of the sheet abuts against the front 1ays29 which have been broughtdown' to the under-guides 28. With the sheetin this position the side-registering member 41 ismoved down to the feed-board edge. and is then moved transversely so that the key-piece 5i of the registering member 41- enters the slot 52 in the feed-board and the member 41 imparts a side-registering movement to the sheet. The-drop guide bar 31' then comes down on to the. sheet and at the sametime or immediately afterwards The drop guide bar 31 rises almost simultaneously with the closing of the. impression cylinder grippers I24 on to the sheet; The drop guide bar 3I holds a sheet stationary at the position of the front lays 29 during the: small interval of time between the lifting of the lays29: and the closing of the impression cylinder grippers I21!- on to theusheet. The holding of the: sheetbythedrop guide bar 3 I. thus. avoids. the-risk: of displacement of the sheet which might occurv if the arms 29awere too slowly or too quickly lifted. As the drop guide bar. 3| makes contentv with the surface of the sheet and .mo-ves in a direction substantially perpendicular to the plane of the sheet there is no tendency to disturb the sheet and there is no practical limit tothe speed at which the bar may be lifted. 7 Also the drop guide bar 3| interposes a barrier between the: hands of the operator and the grippers I24: as the grippers close on to the sheet.

After printing, the sheet may be transferred to a transfer cylinder T and transferred therefrom to a transfer surface T formed on the i mpression cylinder 8 from which transfer surface T it is taken by grippers on the delivery chain 26, all in the manner disclosed in co-pending patent application No. 710,250, filed Nov. 16, 1946; which has matured to Patent No. 2,508,844; issued" on May 23, 1950. It will be appreciated, however, that the present invention is not retrict'ed to use with such transfer and delivery mechanism.

Having described" my invention, I declare that what I claim and desire to secure by Letters Patent is:

l. A printing machine including in combination an impression cylinder which is movable into and out of position to contact with a printing surface, mechanismfor feeding" a sheet to the impression cylinder; mechanism for registering a sheet, mechanism for delivering a sheet from the impression cylinder, a support on which said mechanisms are mounted, eccentric bearings in which the shaft of the impression cylinder is-mounted, means for turning the bearings to move the impression cylinder into and out of contact with the printing surface, means for connecting the support to the bearings, and means carried by the impression cylinder foroperating said 'm'echanisms. i

ing its lower end embracing a boss on-abearing concentric with the shaft. 7

3. A printing machine including. in combine tion an impression cylinder which is movable into and out of position to contact with a printing surface, mechanism for feeding a sheet to the impression cylinder, mechanism for registering a sheet, mechanism for delivering a sheet from the impression cylinder, a support on which said mechanisms are mounted, means for operating said mechanisms, eccentric bearings in which the shaft of the impression cylinder is mounted, means for connecting the support to the eccentric bearings, eccentrics to which the eccentric bearings are connected, a notched disc in driving connection with the eccentrics, a continuously oscillating lever, and a pawl on the lever adapted to engage the notched disc to rotate same and impart a half rotation to the eccentrics to move the impression cylinder into and out of position to contact with a printing surface.

4. A printing machine according to claim 3 wherein the pawl during one operative stroke effects a quarter rotation of the disc which through gearing effects a half rotation of the eccentrics.

5. A printing machine including in combination an impression cylinder which is movable into and out of position to contact with a printing surface, mechanism for feeding a sheet to the impression cylinder, mechanism for registering a sheet, mechanism for delivering a sheet from the impression cylinder, a support on which said mechanisms are mounted, means for operating said mechanisms, eccentric bearings in which the shaft of the impression cylinder is mounted, means for connecting the support to the eccentric bearings, eccentrics to which the eccentric bearings are connected, a notched disc in driving connection with the eccentrics, a continuously oscillating lever, a pawl on the lever adapted to engage the notched disc to rotate same and impart a half rotation to the eccentrics to move the impression cylinder into and out of position to contact with a printing surface, a trip cam which normally covers a notch in the disc to prevent engagement therewith of the pawl, and means for moving the trip cam to a position in which a notch is uncovered and the pawl is allowed to engage therewith.

6. In a printing machine the combination according to claim 5 including perforated grippers on the impression cylinder, a perforated gripper bar with which said grippers co-operate, a vacuum box mounted in the impression cylinder and connected by passageways to the gripper bar, an external vacuum chamber with which the vacuum box intermittently communicates through a port Number 10 in the impression cylinder, a flexible diaphragm mounted in the vacuum box and movable in accordance with the varying pressure conditions in the vacuum box caused by the covering or noncovering of the holes in the gripper bar by a sheet,

. and means for transmitting movement of the flexible diaphragm to the trip cam.

7. A printing machine including in combination an impression cylinder which is movable into and out of position to contact with a printing surface, a feed board for feeding a sheet to the impression cylinder, mechanism for registering a sheet, mechanism for delivering a sheet from the impression cylinder, a support on which said feed board and said mechanisms are mounted, means for moving the support in accordance with movement of the impression cylinder into and out of position to contact with the printing surface, means carried by the impression cylinder to reciprocate the said feed board along the support towards and away from the impression cylinder, and means carried by the impression cylinder for operating said mechanisms for registering and delivering a sheet.

8. A printing machine according to claim 5 including a lock arm normally holding the trip cam in a position covering a notch in the disc and a manually-operable cam which effects movement of said lock arm to release said trip cam and uncover the notch in the disc.

9. A printing machine according to claim 5 including a lock arm normally holding the trip cam in a position covering a notch in the disc and sheet detector mechanism mounted on the impression cylinder and connected to said lock arm to effect movement of the lock arm and uncover the notch in the disc.

10. A printing machine according to claim 5 including an air pressure device, means for varying the air pressure of said device in accordance with the presence or absence of sheets on the impression cylinder, mechanism connected to said device and operable according to variations of pressure therein, and means for transmitting movement of said mechanisms to the trip cam.

FRED SPE-NCE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 546,414 Brooks Sept. 17, 1895 Certificate of Correction Patent No. 2,576,421 November 27, 1951 FRED SPENCE It is hereby certified that error appears in the printed specification of the a ove numbered patent requiring correction as follows:

Column 8, line 70, for the claim reference numeral 5 read 1;

and that the said Letters Patent should be read as corrected above, so that the same nay conform to the record of the case in the Patent Oflice. Signed and sealed this 4th day of March, A. D. 1952.

THOMAS F. MURPHY,

Assistant Gammissioner of Patents. 

